Maple sap spile



United States Patent 3,204,370 MAPLE SAP SPILE Robert M. Lamb, 915 Oswego St., Onondaga County, N.Y. Filed June 26, 1963, Ser. No. 290,774 3 Claims. (Cl. 4752) This invention relates to the collecting of maple sap, and in particular to a spile used with a flexible tubing system of the type disclosed in a publication of the United States Department of Agriculture, Agricultural Research Service, entitled The Use of Plastic Tubing for Collecting and Transporting Maple Sap by C. O. Willits and Lloyd Sipple, identified as ARS 73-35.

I have found in a system of this kind that tree gases evolve from the sap in the spile and in the drop line. The sap is sticky and its surfact tension characteristics results in formation of foam-like gas bubbles. These create a back pressure in the spile and small amounts of sap may be carried upward into the vent. This results in vent clogging and a consequent increased back pressure, with a corresponding resistance to sap flow and a resulting drop in production. At times some sap is forced out of the vent. Formation of gas bubbles in the spile, even when the vent is clear, retards free movement of sap through the spile.

The present invention obviates the tendency of bub bles to remain intact in the spile and sap to be carried into the vent.

For a detailed description of the invention, reference is made to the accompanying drawing, in which:

FIGURE 1 is an elevation, partly in section, showing the spile and associated parts in assembly on a tree, the section of the spile being taken on line 11 of FIGURE 2; and

FIGURE 2 is an elevation of the spile.

A maple tree 11 is tapped in the usual manner and is illustrated with the spile 12 in place. The spile is preferably molded from a conventional plastic material and is provided with a tap-hole nipple 13 providing a sapentrance port, a downwardly projecting tubulation 14 providing a sap-exit port for communicating with a flexible drop line tube 16, and an upwardly projecting tubulation 17, providing an upwardly directed vent port communicating with the vent of vent tube 19. The vent is provided by inserting a straight piece of aluminum wire of smaller diameter than the bore of the vent tube into the end of the tube and bending it to a U-shape as shown at 20.

A chamber 25 is provided in the spile. This chamber communicates at one side with the sap-entrance port, communicates at its top portion with the vent port, and communicates at its bottom portion with the sap-exit port and thence to the drop line tube. The chamber provides space for receiving the tree sap from the tap-hole nipple and for permitting tree gases to evolve from the sap and the bubbles to expand and break, the gas escaping through the vent, While the sap discharges into the drop line tube 16.

The spile is illustrated as made in two parts, the separate cap 26 being sealed in place. The two part structure is provided so that the mold core may be made larger than the sap-entrance and sap-exit ports and withdrawn from the main body of the molded spile.

3,294,379 Fatented Sept. 7, 1965 ice Dimensions of chamber 25 may be varied. The cham-- ber shown is substantially cylindrical with a three-fourths inch diameter and a horizontal axis corresponding in direction to the axis of the sap-entrance port of seveneighths inch. The diameter is enlarged about twice over that of the sap-entrance port, and the horizontal axis is about five times the diameter of the sap-exit port. Such an enlargement provided space for the bubbles to evolve from the entering sap and for the bubbles freely to expand and break. Only gas moves upward through the vent.

Any enlargement of the chamber over the sap-entrance and sap-exit ports will assist to some extent in permitting the bubbles to expand and break. For the best results the chamber should outstretch the bubbles, that is, the bubbles should expand and break without bridging sap films across from wall to wall of the chamber.

The chamber may be as large as desired without interfering with the expansion and rupture of the bubbles. However, to obtain required strength without undue thickness 'of the material, an overly large size would not be selected. The spile is designed to be driven into and pried from the tap-hole. It should be sufficiently rugged to withstand such repeated usage. Enlargement of the chamber tends to weaken the spile.

Although as before indicated the chamber size may be varied, a minimum size of about inch horizontal axis, 3 inch vertical dimension, and /2 inch dimension transverse to the vertical dimension and to the horizontal axis is preferred.

I claim:

1. A spile having a tap-hole nipple for insertion into a tap-hole in a tree providing a sap-entrance port, a downwardly projecting tubulation providing a sap-exit port for communicating with a drop line tube, and an upwardly projecting tubulation providing a vent port for communicating with a vent tube, a chamber in the spile communieating at one side with the sap-entrance port, communicating at its bottom portion with the sap-exit port, and communicating at its upper portion with the vent port, said chamber being enlarged over the sap-entrance and sap-exit ports to provide space for tree gases to evolve from tree sap received in the chamber from the sap-entrance port and to permit the bubbles to expand and break without bridging sap film across from wall to wall of the chamber and the gas to escape through the vent port, the sap discharging from the chamber through the sapexit port.

2. The spile of claim 1 in which the chamber has a minimum size of 7 inch horizontal axis corresponding in direction to the axis of the sap-entrance port, inch vertical dimension, and /2 inch dimension transverse to the vertical dimension and to the horizontal axis.

3. The spile of claim 1 in which the chamber is substantially cylindrical with a inch diameter and a horizontal axis of Vs inch corresponding in direction to the axis of the sap-entrance port.

References Cited by the Examiner UNITED STATES PATENTS 12/91 Goodrich 55-190 10/62 Bilanin 47--52 

1. A SPILE HAVING A TAP-HOLE NIPPLE FOR INSERTION INTO A TAP-HOLE IN A TREE PROVIDING A SAP-ENTRANCE PORT, A DOWNWARDLY PROJECTING TUBULATION PROVIDING A SAP-EXIT PORT FOR COMMUNICATING WITH A DROP LINE TUBE, AND AN UPWARDLY PROJECTING TUBULATION PROVIDING A VENT PORT FOR COMMUNICATING WITH A VENT TUBE, A CHAMBER IN THE SPILE COMMUNICATING AT ONE SIDE WITH THE SAP-ENTRANCE PORT, COMMUNICATING AT ITS BOTTOM PORTION WITH THE SAP-EXIT PORT, AND COMMUNICATING AT ITS UPPER PORTION WITH THE VENT PORT, SAID CHAMBER BEING ENLARGED OVER THE SAP-ENTRANCE AND SAP-EXIT PORTS TO PROVIDE SPACE FOR TREE GASES TO EVOLVE FROM TREE SAP RECEIVED IN THE CHAMBER FROM THE SAP-ENTRANCE PORT AND TO PERMIT THE BUBBLES TO EXPAND AND BREAK WITHOUT BRIDGING SAP FILM ACROSS FROM WALL TO WALL OF THE CHAMBER AND THE GAS TO ESCAPE THROUGH THE VENT PORT, THE SAP DISCHARGING FROM THE CHAMBER THROUGH THE SAPEXIT PORT. 